Key takeaway: App size is not just a storage concern — it is a conversion problem, because a larger app is more likely to be skipped by users, especially those on limited bandwidth or with limited device storage, and reducing app size can meaningfully improve download and install rates.
Why App Size Affects Conversion
App size affects whether users download and install an app. A larger app takes longer to download, uses more bandwidth, and requires more storage, and for users on slow connections, limited data plans, or devices with little free storage, a large app is a real barrier — they may skip it entirely, or abandon the download partway through.
This is why app size is a conversion problem, not just a storage problem — every megabyte of unnecessary size is a potential lost user, and the effect is strongest in markets where bandwidth and storage are constrained, where a large app can be a decisive reason not to install.
Where App Size Comes From
| Source | What it contributes |
|---|---|
| Assets | Images, audio, and video that are larger than needed |
| Dependencies | Libraries that add more than they provide |
| Unused code | Code that is bundled but never used |
| Multiple architectures | Duplicated native code for different devices |
The most common sources of unnecessary size are assets that are larger than needed — images that are not compressed or sized for the device — and dependencies that add more than they provide. Both are easy to accumulate and easy to overlook, and both contribute directly to the app’s size.
The Common Reductions
The most effective reductions target the biggest contributors. Compressing and resizing assets — using the right format, the right dimensions, and the right compression — can dramatically reduce the size contributed by images and media. Removing unused code and dependencies, and using the platform’s mechanisms for delivering code only to the devices that need it, can reduce the size contributed by code.
The key is to measure where the size actually comes from — using the platform’s app size analysis tools — and target the biggest contributors, rather than guessing, since the biggest contributors are often not the ones anyone would guess.
The Trade-Offs
Reducing app size is not free — compressing assets can reduce quality, and removing dependencies can mean reimplementing functionality. The trade-offs need to be weighed, but the conversion benefit of a smaller app often justifies the effort, and many reductions — removing genuinely unused code and assets, using the right format — have little or no downside.
The Bottom Line
Treat app size as a conversion problem, since a larger app is a barrier to download and install, especially for users on limited bandwidth or storage. Measure where the size actually comes from and target the biggest contributors — typically oversized assets and dependencies that add more than they provide — and weigh the trade-offs of reductions, since the conversion benefit of a smaller app often justifies the effort.
